Electrogenerated chemiluminescence from CdS nanotubes and its sensing application in aqueous solution.

Electrogenerated chemiluminescence (ECL) of CdS nanotubes in aqueous solution and its sensing application were studied by entrapping the CdS nanotubes in carbon paste electrode. Two ECL peaks were observed at -0.9V (ECL-1) and -1.2V (ECL-2), respectively, when the potential was cycled between 0 and -1.6V. The electrochemically reduced nanocrystal species of CdS nanotubes could collide with the oxidized species in an annihilation process to produce the peak of ECL-1. The electron-transfer reaction between the reduced CdS nanocrystal species and oxidant coreactants such as S(2)O(8)(2-), H(2)O(2), and reduced dissolved oxygen led to the appearance of the ECL-2 peak. Based on the enhancing effect of H(2)O(2) on ECL-2 intensity, a novel CdS ECL sensor was developed for H(2)O(2) detection. The sensor exhibited a detection limit of 0.1muM and a linear range from 0.5muM to 0.01mM. The relative standard deviations of five replicate determinations of 5muM H(2)O(2) was 2.6%. In addition, the ECL spectrum in aqueous solution also exhibited two peaks at 500 and 640nm, respectively.